This invention relates to an improved method of manufacturing a pipeline from lengths of steel pipe welded together in end-to-end relation, particularly for use in the transmission of wet steam, and wherein the internal surface of each length of pipe is provided with a protective, corrosion-resistant layer prior to the welding operation. Pipelines of this type are primarily used in turbine plants wherein the steam is preferably not susperheated, e.g., in nuclear power plants. The invention relates also to a pipeline constructed in accordance with the improved method.
A method for protection of the internal surface of a pipeline made from steel against erosion or corrosion, or a combination of both, as may occur in pipelines that are subjected to wet, hot steam, is described in a Swedish patent application No. 75 11424-9. The method described in that application can be utilized for pipelines possessing a diameter sufficiently large to permit work to be done inside the pipeline after the pipe lengths have been welded together and installed. It is also feasible to treat the pipe lengths individually prior to welding them together, the welding joints being treated thereafter upon completion of the assembly. Pipelines made from steel and possessing smaller diameters do not permit surface treatment subsequent to completion of the welding operation.